Funds are requested by a group of principal investigators representing nine NIH funded research grants at The Loyola University of Chicago to purchase an instrument system for amino acid analysis and the microsequence determination of peptides and proteins. The system (which includes a Beckman Amino Acid Analyzer and an Applied Biosystems Protein Sequencer, Perkin-Elmer components for high performance liquid chromatography and Hewlett-Packard minicomputer data unit) will provide complete and automated analysis of peptide and protein primary structure at the subnanomole level. The gas-phase microsequencer represents an important advance over liquid or solid-phase instrumentation for automated Edman degradation in terms of sensitivity, reliability and repetitive yield; it is flexibly programmed to perform coupling, cleavage and conversion operations, resulting in amino acid phenylthiohydantoin derivatives ready for direct identification and quantitation. The HPLC system provides an accurate solvent delivery and proportioning system as well as a sensitive and stable variable wavelength detector for amino acid phenylthiohydantoin separation and detection. Finally, the data unit provides computer-assisted analysis which includes baseline subtraction, enhancement of absorbance readings and peak integration. The requested amino acid analyzer and microsequencing system represents a shared multiuser instrumentation package which would provide the institutional armamentarium for protein sequence and would provide a protein structural analysis facility. Location of the requested instrumentation within this research environment would enhance the sharing of information on analytical and sequence approaches and would foster collaboration among the listed investigators. Use of the system would be overseen by our Advisory Committee (consisting of five users plus an outside member) which would have defined responsibilities with regard to instrument operation and the setting of user priorities. Research applications of the microsequencer system span the areas of prokaryotic and eukaryotic molecular biology, membrane proteins and lipoproteins, peptide hormones and hormone receptors, and a variety of enzymes and structural proteins with important biochemical and physiological function. The requested instrumentation would play a pivotal role in permitting sequence determination in each of these cases at the subnanomole level.